1. Field of the Invention
The present invention relates to a developer and a method of a developing process of a resist pattern in a photolithography process.
2. Description of the Background Art
Conventional developing process of a resist pattern in the photolithography, which is one of steps of manufacturing a semiconductor device, is described employing a flow chart in FIG. 3.
First, in a step S1, a semiconductor wafer is coated with a resist material, and afterwards, an exposure is performed employing a certain exposure mask, and a pattern of the exposure mask is printed (a step S2).
Next, in a step S3, in advance of a developing process, a Post Exposure Bake process is performed on the semiconductor wafer.
Afterwards, in a step S4, a temperature of the semiconductor wafer is cooled down approximately to a room temperature.
Next, in a step S5, the semiconductor wafer which the pattern is printed on is mounted on a turntable of a developer, and a developing solution is uniformly dropped on the semiconductor wafer, and afterwards, the developing solution on the semiconductor wafer is agitated by means of a rotation of the semiconductor wafer at a velocity of 10 rpm, approximately for 0.5 seconds in every 5 to 6 seconds (a step S6).
Next, in a step S7, the semiconductor wafer is rinsed with a pure water while being rotated, and afterwards, in a step S8, the semiconductor wafer is dried up and then the serial steps of the developing end.
Here, in the step S6, the developing solution is agitated preventing the defect in the developing. That is, solubility and a velocity of dissolution of the resist into the developing solution vary according to the sort of the resist. Accordingly, as for a static developing, in which the developing is performed with the semiconductor wafer remaining halting after dropping the developing solution on the semiconductor wafer, the developing solution on the resist remains halting. Therefore, on a surrounding of an interface where the resist and the developing solution come in contact with each other, the dissolved resist accumulates and this causes low solubility, and on the other hand, as for the resist of slow solubility, the phenomenon occurs that the behavior of the developing differs between the part where the resist dissolves much (that is, in the positive type resist, the part which has a large exposed area) and the part where the resist dissolves little (that is, in the positive type resist, the part which has a small exposed area) per unit area. This may cause lack of uniformity in the size of the resist pattern or an occurrence of a resist scum. By contrast, when the developing solution is agitated, the developing solution on the interface where the resist and the developing solution come in contact with each other is refreshed, and thus the behavior of the developing can be improved.
As described above, conventionally, the semiconductor wafer is intermittently and slightly rotated for the purpose of agitating the developing solution, however in this method, a migration length per unit time differs between the center and the periphery of the semiconductor wafer (the closer the periphery comes, the more the migration length increases), and thus a flow rate of the developing solution on the semiconductor wafer varies according to a distance from the center of the semiconductor wafer, and the problem remains in that the size of the resist pattern is not always uniform.
The present invention is to provide a developer and a method of a developing process which improve upon uniformity in a size of a resist pattern.
An aspect of a developer according to the present invention includes a substrate rotating system which rotates a substrate of an object of a developing process in-plane and a substrate oscillating system which oscillates the substrate in one-dimensional direction paralleled with a main surface of the substrate by means of oscillating whole of the substrate rotating system in one-dimensional direction. Further, the substrate oscillating system includes a movable supporting part which supports the substrate rotating system, a rail which guides the supporting part to move in one-dimensional direction, and a propulsion supplying source which supplies the propulsion to slide the supporting part along the rail.
According to the developer described above, the substrate oscillating system includes the rail which guides the movable supporting part to move in one-dimensional direction and also slides the supporting part along the rail, therefore, enables the substrate to oscillate in one-dimensional direction paralleled with the main surface of the substrate smoothly with no backlash.
An aspect of a method of a developing process according to the present invention is that it is a method of a developing process of a resist which coats the substrate and also includes steps (a) and (b) described below. That is, this method includes a step (a) indicating exposing after coating the substrate with a resist, and dropping a developing solution uniformly on an entire surface of the substrate and a step (b) indicating agitating the developing solution by means of oscillating the substrate on which the developing solution is dropped in one-dimensional direction paralleled with the main surface of the substrate.
According to the method of the developing process described above, the developing solution on the interface where the resist and the developing solution come in contact with each other is refreshed by means of agitating the developing solution by oscillating the substrate in one-dimensional direction paralleled with the main surface, and thus the behavior of the developing can be improved. Further, the substrate is oscillated in one-dimensional direction, so that a migration length in the entire surface of the substrate per unit time can be uniformed, a phenomenon does not occur that the flow rate of the developing solution on the substrate varies according to the location, the developing solution is refreshed uniformly, the behavior of the developing can be unified, and thus uniformity in the size of the resist pattern can be still improved.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.